4 ct of the brain in a year bad im 21 am i going to get a tumor now?

Ct vs tumor: 4 cts in a year is a good share of radiation, but instead of now worrying over getting a tumor from that, i would make sure to avoid any unnecessary radiation exposure in the future. There is no guarantee it will cause you a tumor of any kind.

Unknown: Most of the data for increased risk of tumors after ct scans of the head come from the pediatric population. A statistically increased risk in adults has not been demonstrated. That being said, i don't think we know where age 21 falls. It is important to avoid excessive radiation scans if it is not needed. In non-urgent situations mris of the brain can provide often times superior images.